The garden itself is genuinely one of the best days out in Wiltshire, but it isn't free — budget for entry if that's the plan. The wider estate walks, including Bonham Wood, are a good free alternative if you just want a walk rather than the full garden experience.
One of the world's great landscape gardens, its centrepiece lake reflecting classical temples, grottoes and rare trees, developed by Henry Hoare from 1741 in the style of an Italian Grand Tour. The paid garden and house sit within a much bigger 2,650-acre estate of chalk downs, ancient woods and farmland, including the free Bonham Wood walk behind the Temple of Apollo, an Iron Age hillfort and the 160-foot Alfred's Tower.
National Trust land — usually free to walk; some sites charge for parking.